double dong

Anyone recommend a good double dong or double dildo? I used the search function here but the search terms are too common.

What it is is my friend and I like to put something in our butts when we masturbate. I thought it would be cool if we could share - you know, lay on the bed with our crotches together and share a double dong in the butt while we masturbate.

I ordered a double dong at primalsins.com called the Jack Black AC/DC Dong. The AC/DC refers to one end is smaller than the other. I think the smaller end is supposed to be four and a half inches around and the larger end is supposed to be six inches around, but when it arrived today, it's more like the small end is five inches around and the large end is seven inches around.

My friend can accommodate bigger than I, but this thing looks like it would be more uncomfortable than pleasurable for both of us. Why is it these things tend to come in anal annihilator sizes? I like a finger but a little larger would be okay. I know LPSG is all about size, but I'm not built that way there.

Any brand names or what have you would be helpful. Also, while I'm at it what dildo materials do you prefer? Thanks.